Optimal valve sizing is critical in transcatheter aortic valve replacement (TAVR) to minimize complications and provide the best clinical and hemodynamic results. The objective of this study was to evaluate whether increasing degrees of transcatheter aortic valve oversizing are associated with differences in patient outcomes following TAVR. A retrospective analysis was conducted to identify patients who underwent TAVR from 2010 to 2025 using our institutional registry. Oversizing was defined as the ratio of the implanted transcatheter heart valve size to the preprocedural annular diameter. Patients were split into 3 groups: minimal oversizing (<10% oversize), moderate oversizing (10% to <20%), and severe oversizing (≥20%). A total of 1,808 patients were included: 180 (10%) in the minimal oversizing group, 433 (24%) in the moderate oversizing group, and 1,195 (66%) in the severe oversizing group. The mean age across groups was 80.0 ± 7.2 years. There were no statistically significant differences in early outcomes, such as valve implantation success rates, postoperative stroke incidence, or new pacemaker implantation among the groups. However, a multivariable analysis demonstrated that the moderate oversizing group was independently associated with a lower all-cause mortality (hazard ratio = 0.63, 95% CI 0.43 to 0.89; p = 0.02), while severe oversizing had equivalent (hazard ratio = 0.82, 95% CI 0.52 to 1.25; p = 0.35). The incidence of paravalvular leak at 1 year and follow-up aortic valve reintervention rates were similar across groups. An oversizing range of 10% to 20% during TAVR was associated with lower all-cause mortality without an accompanying increase in early procedural complications.
Accurate prosthesis selection and sizing are fundamental to the success of transcatheter aortic valve replacement (TAVR). Optimal valve sizing ensures secure anchoring of the transcatheter heart valve (THV), while minimizing complications such as paravalvular leak (PVL), annulus rupture, and conduction disturbances. ,, Despite this shared objective, clinical practice varies widely. Historically, some operators were strong proponents of aggressive oversizing to minimize PVL, whereas others adopted a more conservative approach to avoid the potential complications associated with oversizing, such as conduction disturbance or annual rupture. These divergent clinical philosophies, rooted in earlier device iterations, are now being reevaluated as contemporary THV designs enable more precise, anatomy-conforming implantation. As such, we sought to establish an evidence-based framework to elucidate the impact of varying degrees of oversizing on outcomes following TAVR.
While the importance of valve sizing is well recognized, inconsistency in its definition and quantification continues to challenge standardization. The absence of standardized nomenclature further complicates comparisons across studies. Evidence from Computed tomography (CT)-based analyses indicates that the chosen measurement parameter—area versus perimeter—can markedly influence the calculated degree of oversizing. This variation has important clinical implications, as it affects the balance between minimizing PVL and mitigating the risk of permanent pacemaker implantation. , Furthermore, this debate is complicated by the device-specific nature of valvular oversizing.
In clinical practice, TAVR is increasingly performed in anatomies beyond these recommendations, especially in patients with large annuli, using strategies such as balloon overfilling for balloon-expandable valves or selection of larger supra-annular, self-expanding devices. , This study investigates how the degree of TAVR prosthesis oversizing influences clinical and hemodynamic outcomes.
Methods
The study was approved by our institutional review board. The need for individual informed consent was waived, given the retrospective study design.
Patient population and study design
We performed a retrospective observational study that was done utilizing a prospectively maintained institutional database of TAVR procedures. Definitions and terminology were consistent with those used in the Transcatheter Valve Therapy database. All patients aged 18 years or older who underwent TAVR were included in the study. The degree of oversizing was calculated as oversizing (%) = (THV diameter ÷ native annular diameter) × 100%. × 100%. Patients were split into 3 groups: minimal oversizing (<10% oversizing), moderate oversizing (10% to 20%), and severe oversizing (20% or more).
The primary endpoint was all-cause mortality. Secondary endpoints comprised procedural outcomes and valve hemodynamics, each defined according to Valve Academic Research Consortium-3 criteria. Perioperative outcomes included device success, annular rupture, cardiac tamponade, stroke, and new permanent pacemaker implantation. Hemodynamic outcomes comprised the postprocedural mean aortic valve gradient and PVL severity at 30 days and 1 year.
Statistical analysis
All-cause mortality data were verified by US Social Security Death Index database. Categorical variables were presented by count and percentage; continuous variables were presented by mean ± SD or median with interquartile range (IQR). Then, hazard ratio (HR), 95% CI, and p values were analyzed with Cox regression models. The proportional hazard assumption was tested by evaluating Schoenfeld Residuals. Covariables in the multivariable models were selected based on clinical impact. Variables that were selected for consideration included age, body mass index, left ventricle ejection fraction, hypertension, dialysis, diabetes, chronic obstructive pulmonary disease, atrial fibrillation, peripheral artery disease, stroke, emergent surgery, femoral access, valve type, and the 5-minute walk test. Significance was set at a two-tailed p value <0.05. This analysis was done using SAS version 9.3.
Results
Baseline variables
The study cohort consisted of 1,808 patients who underwent TAVR, including 180 (10%) in the minimal oversizing group, 433 (24%) in the moderate group, and 1,195 (66%) in the severe group. Baseline characteristics for the total patient population are summarized in Table 1 . The severe group included a higher proportion of female patients (n = 597, 50%, p = <0.01). Median age was slightly lower in the moderate oversizing group (79 years; IQR 73 to 84) than in the minimal oversizing group (81 years; IQR 75 to 85) and severe oversizing group (80 years; IQR 74 to 85; p = 0.039). Society of Thoracic Surgeons (STS) risk scores were comparable across the three groups (p = 0.32). Patients in the minimal oversizing group were more frequently classified in higher New York Heart Association functional classes compared with the other groups (p < 0.01). Other comorbidities such as atrial fibrillation, diabetes, and hypertension were similar across the three groups (p = 0.73, p = 0.17, and p = 0.91, respectively). Anatomic measurements reflected the degree of oversizing, with the mean annular diameter smallest in the severe oversizing group (21.0 ± 2.18 mm) and largest in the minimal oversizing group (23.9 ± 2.37 mm; p < 0.01).
Table 1
Baseline characteristics
| Variables (%) |
Minimal oversizing
n = 180 |
Moderate oversizing
n = 433 |
Severe oversizing
n = 1,195 |
p Value |
|---|---|---|---|---|
| Female | 55 (30.6) | 141 (32.6) | 597 (50.0) | <0.01 |
| Age (median [IQR], years) | 81.0 [75.0, 85.0] | 79.0 [73.0, 84.0] | 80.0 [74.0, 85.0] | 0.04 |
| Body mass (median [IQR], kg/m 2) | 28.6 [25.1, 33.3] | 29.1 [25.6, 34.2] | 28.9 [25.1, 33.6] | 0.68 |
| Body surface area (median [IQR], kg/m 2) | 2.0 [1.8, 2.2] | 2.0 [1.8, 2.2] | 1.9 [1.8, 2.1] | <0.01 |
| Left ventricular EF (median [IQR], %) | 58.0 [50.0, 63.0] | 58.0 [53.0, 63.0] | 58.0 [55.0, 65.0] | <0.01 |
| Implanted valve size (mean ± SD, mm) | 25.5 ± 2.45 | 26.2 ± 2.34 | 27.9 ± 2.87 | <0.01 |
| Aorta valve annular diameter (mean ± SD, mm) | 23.9 ± 2.37 | 22.8 ± 2.07 | 21.0 ± 2.18 | <0.01 |
| Aortic valve size (median [IQR], mm) | 25.7 [23.8, 27.9] | 25.5 [23.6, 27.0] | 23.7 [22.0, 25.2] | <0.01 |
| STS risk score (mean ± SD) | 3.3 (2.0 ± 5.3) | 2.9 (1.8 ± 5.1) | 3.0 (1.9 ± 4.7) | 0.32 |
| Mean pressure gradient (median [IQR], mmHg) | 42.5 [36.0, 52.0] | 42.0 [37.0, 51.0] | 42.0 [36.0, 48.0] | 0.58 |
| Aortic valve annular area (median [IQR], mm 2) | 517 [439, 610] | 507 [431, 561] | 435 [376, 489] | <0.01 |
| Self-expandable valve | 2 (1.1) | 43 (9.9) | 1033 (86.4) | <0.01 |
| Balloon-expandable valve | 178 (98.9) | 390 (90.1) | 162 (13.6) | <0.01 |
| NYHA Classification | ||||
| NYHA Class 1 | 5 (2.8) | 14 (3.2%) | 31 (2.6) | <0.01 |
| NYHA Class 2 | 54 (30.0) | 150 (34.6%) | 708 (59.2) | <0.01 |
| NYHA Class 3 | 103 (57.2) | 246 (56.8) | 413 (34.6) | <0.01 |
| NYHA Class 4 | 18 (10.0) | 23 (5.3) | 43 (3.6) | <0.01 |
| Hypertension | 166 (92.2) | 395 (91.2) | 1091 (91.3) | 0.91 |
| Current dialysis | 3 (1.7) | 10 (2.3) | 40 (3.3) | 0.31 |
| Diabetes | 73 (40.6) | 180 (41.6) | 439 (36.7) | 0.17 |
| COPD | 56 (31.1) | 135 (31.2) | 432 (36.2) | 0.11 |
| Prior peripheral artery disease | 27 (15.0) | 68 (15.7) | 144 (12.1) | 0.12 |
| Prior Stroke | 24 (13.3) | 52 (12.0) | 133 (11.1) | 0.65 |
| Urgent/Emergent | 8 (4.4) | 17 (3.9) | 25 (2.1) | 0.05 |
| Prior MI/CABG/PCI | 92 (51.1) | 207 (47.8) | 481 (40.3) | <0.01 |
| Femoral access | 168 (93.3) | 403 (93.1) | 1160 (97.1) | <0.01 |
| Six-minute walk test: Unable to walk | 11 (6.1) | 29 (6.7) | 81 (6.8) | 0.95 |
| Six-minute walk test: Greater than six minutes | 97 (53.9) | 190 (43.9) | 416 (34.8) | <0.01 |
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